Entry 1 sense Webster, 1913 disinfection /dĭs-ĭn-fĕk'-shən/ · dis·in·fec·tion · IPA /dɪsɪnˈfɛkʃən/ 01 n. The act of disinfecting; purification from infecting matter. 1. The act of disinfecting; purification from infecting matter.